1. Field of the Invention
The present invention relates to a process for alkylating an isoparaffin, which process is suitable for obtaining an alkylate gasoline used as a gasoline base having a high octane number.
2. Prior Art
It is the practice under the present situation to decrease the aromaticity of automobile gasoline, and there is required a gasoline base whose aromatic content is small and whose octane number is high. A process for producing alkylate gasoline from isoparaffin and olefin by alkylation is attracting attention.
In the process for producing alkylate gasoline by the above alkylation method, it is known to use, as a catalyst, a liquid catalyst such as sulfuric acid or hydrogen fluoride. It has been also proposed to use a solid catalyst such as crystalline aluminosilicate (JP-B-46-41223), modified zeolite (JP-A-51-68501) or an ultra-acidic zirconia catalyst (JP-A-61-183230).
In the above alkylation method using a liquid catalyst such as sulfuric acid or hydrogen fluoride, not only is it required to carry out a step of separating the reaction product and the liquid catalyst after the reaction, but also there are problems in corrosion of an apparatus and treatment of waste acid.
The alkylation method using the above solid catalyst is excellent by using a liquid catalyst, since it is free of the above problems involved in the method using a liquid catalyst, and since it has advantages of simple reaction operation and durability of an apparatus. However, for example, the alkylation method using an ultra-acidic zirconia catalyst has a disadvantage that the yield of alkylate gasoline is extremely low. It has been therefore desired to develop a novel solid catalyst for alkylation other than the above three solid catalysts for alkylation.